The Commonwealth appeals from an Order suppressing evidence1 entered by the Honorable G. Thomas Gates, Court of Common Pleas, Lebanon County.
*413On October 23, 1981, at approximately 11:40 P.M., Patrolman Louis Laguna of the North Londonderry Township Police Department was on routine patrol. He was accompanied by Police Chief Eldon Beachley. As part of this routine patrol, Officer Laguna drove into the parking lot of the Palmyra Bowling Alley to make sure that there was no loitering in the lot.2 At one end of the parking lot was parked a truck in which sat the appellant and another person. As Officer Laguna approached the truck he detected the odor of burning marijuana and, at the same time, observed the appellant bend over abruptly as if to stuff something underneath his seat. Upon Officer Laguna’s request, the two men presented identification. At this point, Officer Laguna noticed that appellant’s jacket, located on the floor of the truck, appeared to be concealing something. He asked the appellant to lift up the jacket. The appellant did this but quickly dropped it. Officer Laguna asked him again to lift the jacket and the appellant complied, this time exposing a plastic bag containing marijuana. Officer Laguna then read the appellant his rights under Miranda v. Arizona, 384 U.S. 436, 86 S.Ct. 1602, 16 L.Ed.2d 694 (1966), and placed him under arrest. Upon arrival at the police station, the appellant’s jacket was searched and in it were found six small plastic bags, a pipe and a scale. Appellant was charged with one count of possession of a controlled substance3 and one count of possession of a controlled substance with intent to deliver.4
*414The appellant filed a motion to suppress the marijuana and drug paraphernalia on the ground that such evidence was seized pursuant to an illegal search and arrest. Following a hearing conducted cm December 29, 1981, appellant’s motion was granted.
On appeal, the Commonwealth contends (1) under the circumstances of this case, Officer Laguna was justified in conducting a warrantless search of the appellant’s automobile; (2) the appellant voluntarily consented to the search of his automobile; and (3) the search of the appellant’s jacket was valid as incident to a lawful arrest.
The deciding factor in determining whether a warrantless search of a motor vehicle is constitutionally permissible is the existence of reasonable or probable cause. Commonwealth v. Smith, 443 Pa. 151, 277 A.2d 807 (1971); Commonwealth v. Dobkin, 223 Pa.Super. 432, 302 A.2d 457 (1973). Moreover, in considering the reasonableness of a given search or seizure of a vehicle, the need for a warrant is often excused by exigent circumstances. Commonwealth v. Holzer, 480 Pa. 93, 389 A.2d 101 (1978). Such a search is justified because (1) a vehicle is highly mobile and the likelihood is therefore great that it and its contents may never be found if police are prohibited from immobilizing it until a warrant is secured; and (2) one’s expectation of privacy with respect to a motor vehicle is significantly less than that relating to one’s home or office. Id. Furthermore, where an officer who has not intruded into a constitutionally protected area sees contraband in plain view, such evidence may be seized without a warrant. Commonwealth v. Pullano, 295 Pa.Super. 68, 440 A.2d 1226 (1982).
We agree with the Commonwealth that Officer Laguna was justified in conducting a search of the appellant’s truck. In addition to observing the furtive behavior of the appellant who appeared to be stuffing something under his seat, Officer Laguna detected the order of burning marijuana. At the suppression hearing, he testified that it was part of his training at the police academy to be able to *415identify marijuana by its sight and smell. The Supreme Court of the United States has held that an odor may be sufficient to establish probable cause for the issuance of a search warrant. United States v. Ventresca, 380 U.S. 102, 85 S.Ct. 741, 13 L.Ed.2d 684 (1965); Johnson v. United States, 333 U.S. 10, 68 S.Ct. 367, 92 L.Ed. 436 (1948), as cited in Commonwealth v. Stoner, 236 Pa.Super. 161, 344 A.2d 633 (1975). In Commonwealth v. Stoner, Id, this court stated that the rationale used to establish probable cause in those Supreme Court cases applies equally well when determining the validity of a search of a movable vehicle. In Stoner, we analogized a “plain smell” concept with that of plain view and held that where an officer is justified in being where he is, his detection of the odor of marijuana is sufficient to establish probable cause. See also Commonwealth v. Pullano, supra; Commonwealth v. Trenge, 305 Pa.Super. 386, 451 A.2d 701 (1982). In the instant case, it is undisputed that the police officers’ presence in the parking lot was justified as part of their routine patrol. They had been requested by the owner of the lot to watch for loitering. Moreover, the officers were on notice of repeated incidents of loitering in the lot, and, while they were driving past the lot, they observed the appellant and another man seated in a truck. Thus, they were justified in approaching the vehicle. We find, as we did in Stoner, supra, that it would have been a dereliction of duty for Officer Laguna “to ignore the obvious aroma of an illegal drug which he was trained to identify.” Id., 236 Pa.Superi- or Ct. at 166, 344 A.2d 635. We hold, therefore, that there was probable cause to search the appellant’s truck and to seize the marijuana found therein.
We also agree with the Commonwealth’s next argument regarding the search of the appellant’s jacket. The law is clear that a warrantless search is proper if incident to a lawful arrest. Commonwealth v. Plusquellic, 303 Pa.Super. 1, 449 A.2d 47 (1982); Commonwealth v. Rivera, 273 Pa.Super. 105, 416 A.2d 1111 (1979). A warrantless arrest is lawful if the facts and circumstances within the arresting officer’s knowledge are such as would warrant a person of *416reasonable caution to believe an offense has been or is being committed and the person to be arrested is probably the perpetrator. Commonwealth v. Plusquellic, supra; Commonwealth v. Bartlett, 486 Pa. 396, 406 A.2d 340 (1979). Under the circumstances of this case which include the surreptitious behavior of the appellant, the odor of burning marijuana and the discovery of the marijuana underneath the appellant’s jacket, we believe that there was probable cause to arrest the appellant. The subsequent search of the appellant’s jacket and the seizure of the evidence contained therein, were, therefore, valid as incident to this lawful arrest.
In light of the foregoing considerations, we believe that is unnecessary to determine whether the appellant voluntarily consented to the search of his truck.
The Order of the court below is reversed and this case is remanded for trial. This court does not retain jurisdiction.
BECK, J., files dissenting opinion.. Since the Order suppressing the evidence terminates or substantially handicaps the prosecution, such Order is immediately appealable by the Commonwealth. Commonwealth v. Bosurgi, 411 Pa. 56, 190 A.2d *413304, cert. denied, 375 U.S. 910, 84 S.Ct. 204, 11 L.Ed.2d 149 (1963); Commonwealth v. Lapia, 311 Pa.Super. 264, 457 A.2d 877 (1983).
. The record discloses that Officer Laguna and Chief Beachley routinely patrolled this parking lot. Officer Laguna testified at the suppression hearing that, “he asked us, as the police department, to try to stop some of the loitering, due to all the broken beer bottles and things found every morning on the lot." (N.T. December 29, 1981, at 12). Officer Laguna also testified that loitering signs were posted on the doors of the bowling alley. Id.
. 35 P.S. § 780-113(16).
. Id. § 780-113(30).